U.S. patent number 5,851,072 [Application Number 08/756,990] was granted by the patent office on 1998-12-22 for spout construction for bulk box liquid liner.
This patent grant is currently assigned to Custom Packaging Systems, Inc.. Invention is credited to Lee LaFleur.
United States Patent |
5,851,072 |
LaFleur |
December 22, 1998 |
Spout construction for bulk box liquid liner
Abstract
An improved bulk bag or bulk box liner and spout fitment
construction for the liner discharge and/or fill openings. The
liner is of liquid impervious thermoplastic multiple-ply sheet
material, and the spout fitment is a rigid thermoplastic spout of
either open or closed flange type. The spout tube extends through
the liner fitment opening and has an external flange base adjacent
the liner-interior tube end that is permanently affixed and heat
sealed to the liner in a first annular heat weld zone formed
between an outward facing surface of the flange base and the
interior surface of the liner. A first backing piece of liquid
impervious plastic sheet material overlies the inward-facing flange
surface and has a marginal portion overlying the liner interior
surface. A second annular heat seal is formed between this backing
piece and flange base in a second annular weld zone spaced radially
inwardly from the first heat weld seal zone. A third annular heat
seal is formed between the backing piece marginal portion and the
liner interior surface in a third heat annular weld zone spaced
radially outwardly from the first heat weld zone. The spout-liner
construction is thus held in assembly by the three separate and
distinct concentric weld zones. The attachment of backing seals to
the flange base is separate and distinct from the attachment of the
three liner plies to the opposite surface of the flange base.
Likewise, the attachment of the two larger diameter backing pieces
at their outer edge to the inner ply of the liner wall is separate
and distinct from both of the aforementioned attachment and sealing
weld zones. When the rigid spout is of the "open flange" type, the
backing piece has an aperture to fit in close surrounding relation
to the flange tube with the flange base end protruding through the
backing piece aperture into the interior of the liner. When the
spout is of the "closed flange" type, the backing piece is
imperforate and pierceable to open the spout tube liner-interior
end for discharge of liquid therethrough from the liner
interior.
Inventors: |
LaFleur; Lee (Mainstee,
MI) |
Assignee: |
Custom Packaging Systems, Inc.
(Manistee, MI)
|
Family
ID: |
25045896 |
Appl.
No.: |
08/756,990 |
Filed: |
November 26, 1996 |
Current U.S.
Class: |
383/66;
220/258.3; 383/41; 383/906; 383/109; 383/202 |
Current CPC
Class: |
B65D
88/1668 (20130101); B65D 77/065 (20130101); B31B
70/844 (20170801); Y10S 383/906 (20130101) |
Current International
Class: |
B65D
77/06 (20060101); B31B 19/84 (20060101); B31B
19/00 (20060101); B65D 88/16 (20060101); B65D
88/00 (20060101); B65D 033/36 () |
Field of
Search: |
;383/66,80,81,200,202,203,96,906,41,109 ;220/256,258 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Pascua; Jes F.
Attorney, Agent or Firm: Barnes, Kisselle, Raisch, Choate,
Whittemore & Hulbert, P.C.
Claims
I claim:
1. A container having an upright orientation in use with a side
wall and a bottom end, a flexible and collapsible liquid impervious
liner adapted to be received in the container and complementary
thereto and having side, top and bottom walls and fill and
discharge openings through which liquid contents are respectively
entered and discharged, said liner comprising a tubular blank of a
flexible and liquid impervious plastic sheet material, said tubular
blank having a spout fitment in one of the said openings in one of
said walls, said one wall comprises a plurality of plies of said
flexible plastic sheet material, said fitment comprising a
self-supporting rigid spout having a generally cylindrical tube
extending through said liner opening and being openable at opposite
ends thereof, one of said tube ends being disposed interiorly of
said one liner wall and the other of said tube ends being disposed
exteriorly of said one liner wall, said spout also having an
external rigid flange base adjacent said one interiorly disposed
tube end and extending radially outwardly in encircling relation to
said tube, said spout being permanently affixed and sealed at said
one end to said liner by a separate and circumferentially
continuous first annular heat seal formed in a first annular weld
zone between a first surface of said flange base facing toward said
other tube end and an interior surface of said liner and
encompassing said opening of said liner; a first backing piece of
flexible and liquid impervious plastic sheet material overlying a
second surface of said flange base disposed on the opposite side of
said flange base from said first flange surface, said backing piece
being constructed and arranged to radially encompass said one tube
end and to have a marginal portion protruding radially outwardly
beyond the peripheral edge of said flange base and overlying said
liner interior surface, a second separate and circumferentially
continuous annular heat seal formed between said backing piece and
said flange base second surface in a second annular weld zone and
spaced radially inwardly from said first seal in said first weld
zone, and a third separate and circumferentially continuous annular
heat seal formed between said backing piece marginal portion and
said liner interior surface in a third annular weld zone and spaced
radially outwardly from said first weld zone and spaced from both
said first and second seals.
2. The combination of claim 1 wherein said one liner wall comprises
a plurality of plies of said plastic sheet material and all of said
plies are joined to one another and to said flange base first
surface by said first annular heat seal formed in said first
annular weld zone.
3. The combination of claim 2 wherein said one liner wall consists
of two of said plies.
4. The combination of claim 2 wherein said one liner wall consists
of three of said plies.
5. The combination of claim 1 wherein said rigid spout is of the
open flange type and said backing piece has an aperture to fit in
close surrounding relation to said one tube end with said one tube
end protruding through said backing piece aperture into the
interior of said liner.
6. The combination of claim 5 wherein said one liner wall comprises
a plurality of plies of said plastic sheet material and all of said
plies are joined to one another and to said flange base first
surface by said first annular heat seal formed in said first
annular weld zone.
7. The combination of claim 6 wherein said one liner wall consists
of two of said plies.
8. The combination of claim 6 wherein said one liner wall consists
of three of said plies.
9. The combination of claim 1 wherein said spout is of the closed
flange type and said backing piece is imperforate and pierceable
radially inwardly of said second weld zone to thereby open said one
tube end for discharge of liquid therethrough from the liner
interior.
10. The combination of claim 9 wherein a liquid impervious,
imperforate and pierceable plastic sheet seal piece is interposed
between said backing piece and said flange base second surface and
joined to backing piece and flange base second surface by said
second heat seal.
11. The combination of claim 10 wherein the peripheral edge of said
seal piece is generally flush with the peripheral edge of said
flange base.
12. The combination of claim 11 wherein a second backing piece of
liquid impervious imperforate and pierceable plastic sheet material
overlies said first backing piece and has a peripheral edge wider
than the peripheral edge of said first piece marginal portion, said
second backing piece being joined to said first backing piece by a
heat seal formed therebetween and disposed in said third annular
zone.
13. The combination of claim 12 wherein said one liner wall
comprises a plurality of plies of said plastic sheet material and
all of said plies are joined to one another and to said flange base
first surface by said first annular heat seal formed in said first
annular zone.
14. The combination of claim 13 wherein said one liner wall
consists of two of said plies.
15. The combination of claim 13 wherein said one liner wall
consists of three of said plies.
Description
FIELD OF THE INVENTION
This invention relates to a shipping and storage container and,
more particularly to a rigid spout and flexible plastic liner
construction for use primarily with bulk box applications for
shipping liquids in bulk boxes (wood, steel, plastic, corrugated,
etc.), and also for use with a large bulk liquid-container of the
collapsible bag type.
BACKGROUND OF THE INVENTION
Many products, such as granular and liquid materials, are shipped
and stored in large bulk bags adapted to hold as much as a ton or
more of material. The use of bags for this purpose has become
popular because the bags can be shipped from the manufacturer to
the material shipper in a generally flat condition and, if properly
designed, when empty can be returned by the user to the shipper in
the same generally flat condition for reuse. Commercially
successful examples of such bags are disclosed and claimed in U.S.
Pat. Nos. 4,518,106; 4,596,040; 4,781,472; 4,781,473; 4,781,475;
4,790,029; and 4,817,824; 5,087,235; 5,104,236; 5,127,893;
5,328,268; 5,358,335; and 5,142,804, all assigned to Custom
Packaging Systems, Inc., assignee of record herein, and
incorporated herein by reference.
In addition, it is desirable, as set forth in the above identified
patents, to provide the bulk bags with loose and attachable leak
proof liners made of liquid and moisture impervious inexpensive
plastic sheet material which form-fit within the container bag
without pleats or folds in the liner when filled so that no
abnormal stress is put on the liner, the bulk bags can be filled to
maximum capacity, and no valuable product is trapped in the pleats
or folds of the liner. Such liners eliminate dusting or splashing
and container odors during filling or discharging cycles in use of
the bags. Such liners are constructed for insertion into any style
bulk bag and are easily filled. The liners do not elongate out of
the bottom of the bulk bag during discharge due to their attachment
features to the exterior bag, such as tape-tab and sewing
techniques which holds the liner permanently in place, or a
tape-tab and tied feature which allows removal of a used liner and
a new liner to be inserted and tied into the bag, thereby allowing
reuse of the outer bag. Use of such liners in the outer bulk bags
saves on cleaning, storage of waste, and container replacement
costs. Additionally, liners constructed in accordance with the
aforementioned patent disclosures may be quickly inserted into the
outer woven bag and inflated in seconds to correctly fit the bag
container.
The liners can be provided in a variety of single or multi-ply
plastic sheet materials to prevent problems related to corrosion,
oxygen, moisture, conductivity, high temperature, and static
electricity. Additionally, such bulk liquid bag liners can be
provided with rigid inlet and/or outlet spout fitments to control
liquid product inflow and outflow and easy closure.
Despite the many advantageous characteristics and features of the
aforementioned patented bulk bag and liner constructions, there
remains a need to improve the attachment connection of the rigid
spouts as used in inlet and discharge liner fitments to the liner
in a secure, liquid-tight and leak proof manner. Typically such
rigid spouts are commercially available as separate components and
injection molded of suitable plastic materials. The cylindrical
tube barrel that defines the main conduit of the spout is normally
provided with an integral outwardly extending flange base that
encircles the barrel and is adapted for attachment to the single or
multi-ply plastic material of the liner, which in turn is suitably
apertured to receive the spout therethrough. Typically, such rigid
spout fitments are referred to in the trade as a "fill flange" and
"discharge flange" because of their characteristic mounting flange
base portion, which in turn is often referred to as the "flange
base".
Such commercially available fill and discharge flanges may be of
the "open flange" type, which means that the spout barrel may be
provided with an externally or internally threaded portion adapted
to threadably receive a removable closure plug or cap that is
accessible externally of the liner to open and close the flange.
Another type of such flange is the "closed flange" type that is
initially manufactured in closed condition by attachment thereto a
sheet of sealing material adhesively attached, as by a heat seal
weld, to the flange base so that the closed flange can only be
opened by piercing this seal piece, to rupture it and thereby open
the flange after external coupling connections have been made to an
external fill or discharge hose or conduit.
Typically, in manufacture of prior liner constructions employing
such fill and discharge flanges, one or more plies of thermoplastic
liner sheet material were heat sealed to the thermoplastic material
of the flange base by use of a heat sealing head fixture of the
either the induction heater or ultrasonic welding type, such as
that disclosed in U.S. Pat. No. 3,916,148 and referenced in the
above-noted U.S. Pat. No. 5,087,235, both incorporated herein by
reference. This created a single annular zone of a fused ring of
heat welded fused plastic material that was formed between the
liner ply and the base surface encircling the flange barrel. In the
case of closed flange, either simultaneously or successively, one
or more barrier seal pieces thermoplastic sheet material were often
heat sealed to the opposite side of the flange base to form an
interior seal membrane, the fusion welding zone being aligned or
registered with that of the ply or plies welded to the opposite
side of the flange base.
It has been found that this prior spout-to-liner attachment
construction, although generally satisfactory under most usage
conditions, in some instances has not provided a leak-proof spout
fitment system. Such fitments are subject to occasional development
of "leakers" due to "over cooked" seals, resulting when the heat
weld joint is stressed in tension, in a tearing action along a seal
edge, thereby causing leaking next to the outside of the seal edge
during bag transit, or even before filling the bag liner with any
liquid at all. It will be understood that, particularly in the case
of discharge fitments for bulk liquid bag liners, that the same are
subjected to severe hydraulic stresses from the weight of the
filled bag liquid contents while in transit, and to additional
shock stresses from bumping or mishandling while being moved from
storage to the discharge station as by forklifts, overhead cranes
and the like. In addition, in the prior manufacture of such
spout-to-liner constructions several separate manufacturing steps
are often required that involve rehandling of the product and
therefore increased possibility of processing errors and defects
resulting from successive tolerance stack-ups.
OBJECTS OF THE INVENTION
Accordingly, among the objects of the present invention are to
provide an improved liner fill and/or discharge spout fitment
construction, preferably employing commercially available open or
closed type rigid flanges components, which is economical to
manufacture and yet which provides enhanced liquid-tight sealing
characteristics, that can safely withstand greater static hydraulic
stresses than prior liner spout fitment constructions so as to
assure that the discharge and fill fitments will be secure and
leak-proof in storage and use, which has an improved ability to
absorb the dynamic hydraulic and mechanical stress loads placed on
the flange while a filled bag is in transit, which enables reduced
handling of the liner and spout component materials during
construction and readily lends itself to improvements in process
control and subsequent product quality as a result of less
handling, enhanced monitoring capabilities, defect traceability and
simplified production procedures.
A further object is to provide an improved method of constructing a
bulk box liner and spout fitment assembly for economically,
reliably and consistently achieving an improved liner and fitment
construction of the aforementioned character.
SUMMARY OF THE INVENTION
In general, and by way of summary description and not by way of
limitation, the invention achieves the foregoing objects by
providing an improved liner spout fitment construction for the
liner discharge and/or fill openings through which liquid contents
are respectively discharged from and filled into the liner.
Typically the liner is made from a tubular blank of liquid
impervious plastic sheet material, and the spout fitment is mounted
in one of such liner openings. The fitment preferably comprises a
commercially available self-supporting rigid spout of either open
or closed flange type and having a generally cylindrical tube
extending through the liner fitment opening and open at its
opposite ends. The spout flange also has an external rigid flange
base adjacent the liner-interior tube end that extends radially
outwardly in encircling relation to the tube. The spout flange is
permanently affixed and sealed to the liner in a first annular heat
weld zone by a circumferentially continuous first annular heat seal
formed in and between a first surface of the flange base and the
interior surface of the liner and encompassing the liner opening
within the liner interior. A first backing piece of liquid
impervious plastic sheet material overlies a second base flange
surface opposite the base flange first surface. This backing piece
is constructed and arranged to radially encompass the
liner-interior tube end and to have a marginal portion protruding
radially outwardly beyond the peripheral edge of the flange base
overlying the liner interior surface. A second annular heat seal is
formed between this backing piece and flange base in a second
annular weld zone spaced radially inwardly from the first heat weld
seal zone. A third annular heat seal is formed between the backing
piece marginal portion and the liner interior surface in a third
heat annular weld zone spaced radially outwardly from the first
heat weld zone.
Preferably the liner wall comprises a plurality of plies of the
plastic sheet material and all of such plies are joined to one
another and to the flange first surface by the first annular heat
seal formed in the first annular weld zone.
In one embodiment the rigid spout is of the "open flange" type, and
the backing, piece has an aperture to fit in close surrounding
relation to the flange tube with the flange base end protruding
through the backing piece aperture into the interior of the
liner.
In another embodiment the spout is of the "closed flange" type, and
the backing piece is imperforate and pierceable to open the spout
tube liner-interior end for discharge of liquid therethrough from
the liner interior. An imperforate and pierceable plastic sheet
seal piece is interposed between the backing piece and base flange
surface and joined to the backing piece and flange base by the
second heat seal. Preferably, the peripheral edge of the seal piece
is generally flush with the peripheral edge of the flange base. A
second backing piece of liquid impervious imperforate and
pierceable plastic sheet material overlies the first backing piece
and has a peripheral edge generally flush with the peripheral edge
of the first piece marginal portion. The second backing piece is
joined to the first backing piece by a heat seal formed
therebetween and disposed in the third annular weld zone.
It thus will be seen that the spout-liner construction is held in
assembly by three discrete concentric weld zones. The attachment of
backing seals to the flange base is separate and discrete from the
attachment of the three liner plies to the opposite surface of the
flange base. Likewise, the attachment of the two larger diameter
backing pieces at their outer edge to the inner ply of the liner
wall is discreet from both of the aforementioned attachment and
sealing weld zones. Hence, any production imperfection that may
creep in to any one of these attachments heat weld zones will not
affect the liquid sealing provided by the remaining two attachment
zones. Moreover, the stresses imposed by the hydraulic forces
created by the liquid contents of the bag tending to place the
various plastic sheets in tension relative to the flange base are
well distributed through the three zones of welded attachment to
thereby better withstand such rupture-inducing stress loads.
In addition, there is no danger that, in performing the welding
procedure in each of these discrete, radially spaced weld zones,
"overcooking" can occur with respect to a previously formed weld
ring. Accordingly, the liner/spout construction of the invention
avoids weakening of the weld ring joints or otherwise potentially
introducing a sealing defect which could contribute to product
leakage under the stresses encountered by the liner/spout
construction in its normal intended use.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing as well as other objects, features and advantages of
the present invention will become apparent from the following
detailed description of preferred but exemplary embodiments of the
invention and of the best mode presently known for making and using
the invention, and from the appended claims and accompanying
drawings, in which:
FIG. 1 is a simplified perspective view of a bulk box liner as it
appears when full when resting on a flat supporting surface and
confined laterally such as by a square open-ended reinforcing
container (not shown), and embodying a first embodiment discharge
fitment construction of the invention;
FIG. 2 is a part elevational, part sectional fragmentary view taken
on the line 2--2 of FIG. 1 illustrating the discharge fitment of
FIG. 1 greatly enlarged thereover and showing of the final sealing
step, sealing all plies of the liner to the outer flange seal
surface;
FIG. 3 is a part elevational, part center sectional view of the
closed flange of FIGS. 1 and 2, illustrating a first step wherein
two seal members are applied as a multiple ply seal laminate to the
underside of the flange base in a separate manufacturing step in
the performance of the method of the invention;
FIG. 4 illustrates a second step of a method wherein the
intermediate product of FIG. 3 is assembled to an innermost ply of
the multiple-ply liner in performing the method of the invention,
the innermost ply and closed flange being shown fragmentarily;
FIG. 5 is a fragmentary, part elevational, part center sectional
view of a liner-to-spout construction of a second embodiment of the
invention employing an open flange fitment constructed in
accordance with the method of the invention;
FIG. 6 is a fragmentary, part elevational, part sectional view
illustrating a first step in the method of constructing the
embodiment of FIG. 5;
FIG. 7 is a view similar to that of FIG. 6 illustrating a second
step in the method of constructing of the embodiment of FIG. 5;
and
FIG. 8 is a view of illustrating the open flange fitment in
elevation and diagrammatically illustrating the first step being
performed in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
Referring now in more detail to the accompanying drawings, FIG. 1
illustrates a first embodiment of a plastic liner 10 shown by
itself prior to insertion into an associated bulk-liquid material
box, bulk bag or other container of the aforementioned type. Liner
10 is shown diagrammatically as it would appear when filled and
confined in a rectangular outer restraining container. Preferably,
liner 10 of the first embodiment is constructed of 4 millimeter
thickness, ultraviolet resistant, low density polyethylene of from
1-3 ply thickness to provide a high strength liquid impermeable
interior lining for the associated outer bulk bag. The upper end of
liner 10 is provided with a standard rigid fill flange 12, which
may be of type commercially available and known as an L.B.
Transport flange with cap or a Waddington Duval fill flange with
Tri-Sure plug, and attached to the liner in a conventional manner.
There are several other brands of suitable flanges. Liner 10 may be
constructed similar to liner 92 described in conjunction with FIG.
18 of the aforenoted U.S. Pat. No. 4,596,040 incorporated herein by
reference and therefore not further described in detail.
One of the side wall panels 14 of liner 10 is provided adjacent its
lower edge with a rigid dispensing spout construction 16 in
accordance with the present invention and shown in more detail with
reference to FIG. 2. The liner/spout construction 16 includes a
commercially available discharge flange 18, such as a 2 inch
diameter rigid Waddington Duval flange, which is injection molded
of suitable thermoplastic material and has a cylindrical barrel 20
provided with an interior throughbore (not shown) and having a thin
flat flange base 22 protruding radially outwardly from its interior
end. Base 22 typically is circular in plan configuration with
parallel flat top and bottom surfaces 24 and 26 but may also be
rectangular or square and a suitably shaped heat sealing device
would be used.
In order to construct the spout-liner construction 16 in accordance
with the method of the invention, and as shown in FIG. 3, a first
assembly step is performed "out of line", i.e., separate from the
subsequent manufacturing production line procedures employed in
attaching dispensing flange 18 to the three plies of liner 14. The
sub-assembly of FIG. 3 is thus made by attaching to flange base 22
two thin sheets 28 and 30 of thermoplastic backing material, such
as ultraviolet resistant, low density polyethylene, to form a
two-ply liquid imperforate seal barrier across the inner end of
barrel 20. The uppermost seal ply piece 28 preferably has the same
diameter of base 22 and is registered with its outer edge flush
with that of base 22. The lowermost ply piece 30 of the
sub-assembly preferably is likewise circular in plan, but made of a
predetermined larger diameter, for example 125% of the diameter
base 22, and arranged concentrically with ply 28 and base 22. As
diagrammatically illustrated in FIG. 3, ply 28 is heat sealed and
attached by a circular ring weld 32 to the underside 26 of base 22,
and ply 30 is also sealed and attached by a circular ring weld 34
to the underside of ply 28. Preferably, the two weld rings 32 and
34 are formed concurrently on the same weld zone by fixturing the
stack-up of base 22, ply 28 and ply 30 as shown in FIG. 3 against
conventional electric heat sealer bars in a circular configuration
such as disclosed in U.S. Pat. No. 3,916,148, as is well understood
in the art.
The next step in the method is illustrated in FIG. 4. In this step
the sub-assembly of FIG. 3 is brought against the innermost ply 38
of the three-ply side panel 14 of liner 10, and barrel 20 inserted
outer end first through a suitable opening 36 provided in ply 38 so
as to bring the undersurface of ply 38 flush against upper surface
24 of flange base 22. The two outer plies 40, 42 (FIG. 2) of side
wall 14 are held spaced away from the outer end of flange 18 during
this procedure. Then a third circular seal backing piece 44, having
the same diameter as backing piece 30, is laid against backing 30
within the outer edge flush. Backing pieces 30 and 44 are then
fixed to inner liner ply 38 by forming a heat seal ring weld 46
between backing piece 30 adjacent its outer edge, and likewise a
second heat seal weld ring 48 between backing 44 and backing 30 in
registry with weld 46. Preferably, the ring welds 46 and 48 are
formed simultaneously in the same weld zone by fixturing the
three-ply stack up of liner ply 38 and pieces 30 and 44 in a
suitable conventional electric heat welding head aligned
concentrically over the welding zones where weld rings 46 and 48
are to be so formed.
As shown in simplified form in the in-line production progression
from FIG. 4 to FIG. 2, in the next step in the method of
constructing the spout-liner fitment 16, the two outer plies 40 and
42 are suitably apertured to provide openings 50 and 52 therein,
and then barrel 20 inserted outer end first therethrough to bring
these plies down flat against ply 38, as shown in FIG. 2. Then all
three plies 38, 40 and 42 of liner wall 14 are affixed to top
surface 24 of flange base 22 by forming three mutually registered
weld rings 54, 56, and 58 disposed respectively between inner ply
38 and the top surface 24 of base 22, between plies 38 and 40 and
between plies 40 and 42, as shown in simplified form in FIG. 2.
Again, preferably, the three weld rings 54, 56 and 58 are formed
concurrently in the same weld zone by fixturing the three-ply stack
up 38, 40 and 42 against base 22 with a suitable electric heat
sealing or welding bars in a fixture aligned with this weld zone
54, 56, 58.
With spout-liner construction 16 completed as shown in FIG. 2 the
same is now ready for use with the flange 18 securely affixed to
liner side wall 14 and sealed by three liner-interior barrier
layers 28, 30, and 44 spanning in liquid-tight relation the inner
end of the throughbore of flange barrel 20. It will also be seen
that the spout-liner construction is held in assembly by three
separate or distinct weld zones: (1) the radially innermost weld
zone 32, 34, (2) the radially outermost weld zone 46, 48; and (3)
the radially intermediate weld zone 54, 56, 58. Thus the attachment
of backings seals 28 and 30 to base 22 is separate and distinct
from the attachment of the three liners plies 38, 40 and 42 of the
liner wall 14 to the opposite surface 24 of base 22. Likewise the
attachment of the two larger diameter backing pieces 30 and 44 at
their outer edge to the inner ply 38 of the liner wall is separate
and distinct from both of the aforementioned attachment and sealing
weld zones. Hence, any production imperfection that may creep into
any one of these attachments zones will not affect the liquid-tight
sealing provided by the remaining two attachment zones. Moreover,
the stresses imposed by the hydraulic forces created by the liquid
contents of the bag tend to place the various plastic sheets in
tension relative to flange base 22 are well distributed through the
three zones of welded attachment to thereby better withstand such
rupture-inducing stress loads.
When the contents of the bag containing liner 10 are to be
discharged, the interior liquid seal provided by the three plies
28, 30 and 44 are opened by cutting out their central area aligned
with the interior bore of the barrel 20, as by use of a suitable
piercing tool to thereby allow liquid contents to fill therethrough
and out of flange 18 into an associated hose or other discharge
conduit. However, it will be noted that even after these three
interior barrier plies are ruptured the same remain attached to
base 22 as well as to inner liner 38 through the two discrete weld
zones 32, 34, and 46, 48 respectively. Hence the additional
reinforcement of the attachment of the three-ply wall 14 to flange
18 remains intact and in sealed relation to prevent leakage past
the exterior of flange 18 from the interior of liner 10.
Second Embodiment
FIGS. 5-8 illustrate a second embodiment of a liner/spout
construction 16' wherein elements previously described are given
like reference numerals, and those alike in structure and function
are given like reference numerals raised by a prime suffix, and
their description not repeated. In the second embodiment of the
liner/spout construction 16' of the invention, the application of
the principles of the invention are shown applied to a rigid
discharge spout 80 of the "open flange" type, such as that
commercially available as a Scholle Buttress Plug, a Waddington
Duval flange with Tri-Sure plug or a L.B. Transport flange with
cap. As best seen in FIG. 8, flange 80 has a cylindrical barrel
20', a straight through-flow passage open at both ends of the
fitment (not shown), and a threaded spout neck 82 threadably
receiving a removable sealing cap (not shown). Spout 80, like spout
18, has an external flange extending integrally from barrel 20' to
form the thin, flat, circular flange base 22'.
The first step of the method of the invention employed in
constructing liner/spout 16', shown in finished form in the
simplified view of FIG. 5, is illustrated diagrammatically in FIG.
8. A circular backing piece 30', which may be of the same material
as one of the plies 38-42 of liner wall 14, is circularly apertured
to slip over the lower end of barrel 20' of flange 80 so as to
closely encircle barrel 20', and is brought against the
undersurface 26' of flange base 22' and then affixed thereto in a
first weld zone by a heat seal ring weld 34' concentrically
encircling barrel 20' and spaced slightly radially outwardly
therefrom. Backing piece 30' is diametrically dimensioned to
protrude radially outwardly beyond the outer edge of flange base
26' as so affixed, as illustrated in the corresponding view of FIG.
6. Preferably, the diameter of piece 30' exceeds that of flange
base 22' by approximately 125%. Again, it is to be understood that
the performance of the first step illustrated in FIGS. 6 and 8,
i.e., the affixation of backing piece 30' to flange 80, is
preferably performed as an "out of line" procedure performed at a
production station separate from the remaining in-line assembly
construction of liner/spout 16'.
In the next step of the second embodiment method, as illustrated in
FIG. 7, the innermost ply 38 of liner wall 14 is suitably
circularly apertured to slip over the upper end of spout 80 so that
when laid on upper surface 24' of flange base 22' the same closely
encircles flange barrel 20' and rests on upper surface 24'. Then
the outer margin of backing piece 30' is affixed to the
liner-interior surface of ply 38 in a second weld zone by a heat
seal ring weld 48', again as by employing a suitable conventional
electric heater bar welding head fixture. Welding 48' is located
adjacent the outer edge of backing piece 30' and is spaced radially
outwardly away from the outer edge of flange base 22', similar to
weldings 46 and 48 of the first embodiment. Also, it is to be
understood that in the performance of the second step illustrated
in FIG. 7, the outer two plies 40 and 42 of liner wall 14 are held
spaced away from flange 80 and innermost ply 38 so as not to
interfere with the performance of this step.
In the final step of the second embodiment method the outer two
plies 40 and 42 of liner wall 14 are suitably cut to form a
circular hole, the cut-out film being removed and discarded, and
then these other two plies brought to their assembled position on
flange 80 as shown in FIG. 5. Then the aforementioned weld rings
54, 56 and 58 are formed in a third weld zone as in the manner of
the first embodiment to sealably join together the three plies 38,
40 and 42 and to securely affix this welded lamination to upper
surface 24' of flange base 22'. It is again to be noted that the
annular zone of weld rings 54, 56 and 58 is separate and distinct
from and disposed radially of flange 80' intermediate the innermost
weld zone of weld ring 34 and the outermost weld zone of weld ring
48'. Hence, there is no danger that, in performing the welding
procedure in each of these separate and distinct, radially spaced
weld zones, "overcooking" can occur with respect to a previously
formed weld ring. Accordingly, the liner/spout construction of the
invention avoids the welding joints or otherwise potentially
introducing a sealing defect which could contribute to product
leakage under the stresses encountered by the liner/spout
construction 16' in its normal intended use.
ADVANTAGES
In addition to the advantages described previously, from the
foregoing description it will now be understood by those skilled in
the art that the leak proof discharge system, construction and
method of the invention amply fulfills the foregoing objects and
provides many additional advantages. The improved structural
integrity of the liner/spout constructions 16 and 16' is such that
they provide the ultimate in customer satisfaction in that the
customer can be assured that their bulk liquid bag discharge
fitments will be secure and leak proof. The integrity of the
multiple backings 28, 30, and 34 for the closed flange construction
16 and the independent arrangement of the separate and distinct
weld ring attachment and sealing zones provides an improved ability
to absorb the hydraulic stresses placed on the flange while in
transit. Moreover, even after barrier seal pieces 28, 30 and 44 are
punctured to open the fitment for bag content discharge weld rings
32 and 34 and 46 and 48 remain intact as barriers against leakage
around the discharge fitment. Likewise, in the case of the open
fitment construction 16' of the second embodiment, the internal
backing piece 30' provides an independent safeguard against leakage
that supplements the weld zone rings 54, 56 and 58, both during
transit and content discharge.
The fitment construction of the invention also lends itself to
improved manufacturing efficiency through reduced handling of
product and enables several existing processes to be integrated
into fewer steps. Process control and subsequent product quality is
also improved as a result of less handling, enhanced monitoring
capabilities, traceability and simplified production procedures.
The initial steps in the construction of the first and second
embodiments illustrated respectively in FIGS. 3 and 6, 8 are
readily done as an out-of-line procedure to form sub-assemblies,
thereby ensuring improved product integrity and enhanced hygienic
procedures.
The liner/spout construction of the invention has been found to
overcome the problem of "over cooked" seals of prior liner-spout
constructions that resulted in a tearing action along a seal edge,
thereby causing leaking next to the outside of the seal edge during
transit and in use, or tearing even as initially constructed prior
to filling the liner with liquid. Stress testing of the new
construction also shows improved results over prior constructions
in terms of less damage to the flange seal area.
It will also be understood that the rigid spout constructions of
the invention also can be employed as liner fill fitments, and can
be located in various suitable fill and/or discharge locations on
one or more of the walls of liner 10.
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